WET Compressor VST3 Plugin

Easy to use FET compressor with high resolution metering. Get to a great sound in seconds!

Download: wetvst.com/wetcompressor

Panel too big or too small? Right-click anywhere on the panel and pick UI Zoom, from 50% to 125%.

Features

• Easily dial in the right response using the hand-tuned Fast, Normal and Slow presets
• Quickly set levels using the stepped INPUT and OUTPUT, 21 positions each, fixed threshold and ratio
• Classic sound: pushing the unit makes the sound slightly overdriven for a more authorative sound
• Closely monitor the unit operation using the real-time gain reduction and I/O LED metering
• Now also with external side chain input (selectable by right clicking the main panel)
• Resizable panel: right-click and zoom from 50% to 125%
• INPUT drives the signal past a fixed threshold, OUTPUT puts back what that cost
• Full parameter automation in every major DAW

Download & Installation

Windows

1. Download the latest release from wetvst.com or GitHub Releases
2. Extract the ZIP file
3. Copy WetCompressor.vst3 to your VST3 folder:
   • User: C:\Users\[Username]\Documents\VST3\
   • System: C:\Program Files\Common Files\VST3\
4. Restart your DAW and rescan plugins

Linux

1. Download the latest release from wetvst.com or GitHub Releases
2. Extract the ZIP file
3. Copy WetCompressor.vst3 to your VST3 folder:
   • User: ~/.vst3/
   • System: /usr/lib/vst3/
4. Restart your DAW and rescan plugins

macOS

1. Download the latest release from wetvst.com or GitHub Releases
2. Extract the ZIP file
3. Copy WetCompressor.vst3 to your VST3 folder:

   ~/Library/Audio/Plug-Ins/VST3/
   

4. Copy WetCompressor.component to ~/Library/Audio/Plug-Ins/Components/ for Logic and GarageBand
5. Restart your DAW and rescan plugins

Note that by default, the Library folder may not be shown in the Finder. See the macOS documentation on how to make it visible.

The plug-in is signed and notarised by Apple, so macOS opens it without a warning.

If macOS still blocks it

Older releases were not signed. If macOS says the plug-in "cannot be opened because the developer cannot be verified", remove the quarantine flag in Terminal and restart your DAW:

xattr -cr ~/Library/Audio/Plug-Ins/VST3/WetCompressor.vst3
xattr -cr ~/Library/Audio/Plug-Ins/Components/WetCompressor.component

Usage

1. Load the plugin in your DAW (Reaper, Cubase, Ableton Live, FL Studio, etc.)
2. Turn up INPUT until the gain-reduction meter shows the amount you want - this is the compression control, there is no threshold knob
3. Pick a timing with FAST, NORMAL or SLOW
4. Bring OUTPUT up to make up what the compression took
5. Automate any of the three for creative effects

Sidechain input

You can now have the compressor "duck" on a kick drum for instance. Right-click the plug-in window and select "Detector: Sidechain" to set it up.

• Send the signal the compressor should listen to into the plug-in's input 3/4 (mono on 3 works too)
• Detector: Main (default) listens to input 1/2, as before
• With nothing on 3/4 and Detector set to Sidechain, there is no compression
• The choice is saved with your project

Parameter Reference

Parameter	Range	Default	Description
Input	21 detents of 3 dB, +/-30 dB (1 dB with Shift)	0 dB, centre detent	Drive into the gain cell. More input is more compression
Output	21 detents of 3 dB, +/-30 dB (1 dB with Shift)	0 dB, centre detent	Makeup gain after the output stage
Mode	0-2	1 (NORMAL)	0=FAST, 1=NORMAL, 2=SLOW
Detector	0-1	0 (Main)	0=Main (input 1/2), 1=Sidechain (input 3/4). Right-click menu

Timings

Setting	Attack	Release
FAST	1 sample	89 ms
NORMAL	0.07 ms	278 ms
SLOW	0.18 ms	819 ms

All three attack settings are under a millisecond, as on the original hardware - its whole attack range is 20 to 800 microseconds. SLOW here is still faster than most compressors at their fastest.

Mouse

• Wheel: one detent per notch, or 1 dB with Shift held
• Shift-drag: fine adjust, three steps inside every detent
• Ctrl-click or double-click: back to 0 dB
• Right-click the panel: UI Zoom, from 50% to 125%, and Detector: Main or Sidechain

Building from Source

If you want to build the plugin yourself, follow these instructions.

System Requirements

Windows

• Operating System: Windows 10/11 (64-bit)
• Build Tools:
  • Visual Studio 2022 Build Tools or Community Edition
  • CMake 3.15 or higher
  • Git

Linux

• Operating System: Linux (x86_64)
• Build Tools:
  • GCC or Clang with C++17 support
  • CMake 3.15 or higher
  • Git
• Dependencies (Ubuntu/Debian):

  sudo apt-get install cmake gcc g++ libstdc++6 libx11-xcb-dev libxcb-util-dev \
      libxcb-cursor-dev libxcb-xkb-dev libxkbcommon-dev libxkbcommon-x11-dev \
      libfontconfig1-dev libcairo2-dev libgtkmm-3.0-dev libsqlite3-dev \
      libxcb-keysyms1-dev git
  

macOS

• Operating System: macOS 10.13 or higher (Intel) / macOS 11.0 or higher (Apple Silicon)
• Build Tools:
  • Xcode Command Line Tools or Xcode
  • CMake 3.15 or higher
  • Git

Step 1: Clone VST3 SDK

If the vst3sdk folder is not present, clone it:

git clone --recursive https://github.com/steinbergmedia/vst3sdk.git

Step 2: Build

Windows

Run the automated build script:

build.bat

This will:

• Configure CMake for Visual Studio 2022
• Build the plugin in Release mode
• Run the VST3 validator (47 automated tests)
• Output: WetCompressor\build\VST3\Release\WetCompressor.vst3

Linux

Run the automated build script:

chmod +x build.sh
./build.sh

This will:

• Configure CMake with GCC/Clang
• Build the plugin in Release mode
• Run the VST3 validator (47 automated tests)
• Output: WetCompressor/build/VST3/Release/WetCompressor.vst3

macOS

Run the automated build script:

chmod +x build.sh
./build.sh

This will:

• Configure CMake with Clang
• Build the plugin in Release mode
• Run the VST3 validator (47 automated tests)
• Output: WetCompressor/build/VST3/Release/WetCompressor.vst3

Step 3: Install

Windows

To install the plugin to your system's VST3 folder:

install.bat

Note: You may need to run as Administrator if you encounter permission errors.

Linux

To install the plugin to your user VST3 folder:

chmod +x install.sh
./install.sh

This installs to ~/.vst3/WetCompressor.vst3

macOS

To install the plugin to your user VST3 folder:

chmod +x install.sh
./install.sh

This installs to ~/Library/Audio/Plug-Ins/VST3/WetCompressor.vst3

---

Technical Details

Architecture

• Framework: VST3 SDK (Official Steinberg)
• Language: C++17
• Build System: CMake (MSBuild on Windows, Make on Linux)
• GUI: VSTGUI4

Audio Processing

• Host Sample Rates: Supports 22.05 kHz to 384 kHz
• Internal Sample Rate: Host rate - nothing is resampled, quantised or band-limited
• Host Bit Depth: 32-bit float processing
• Ratio: 4:1 closed loop, softening to 3.7:1 as the cell runs out
• Threshold: -20 dBFS, fixed
• Maximum Reduction: 38 dB
• Latency: 0 samples
• CPU Usage: <0.5% (typical)

Implementation Details

• Gain Cell: FET as a shunt voltage-controlled resistor, with a drain-to-gate divider cancelling most of the square-law term
• Q-Bias: A standing gate voltage, so the cell is never fully out of circuit
• Detector: Peak rectifier taken after the gain cell, linked across the stereo pair
• Sidechain: One attack constant, two release constants in parallel, slow path weighted by depth
• Input Transformer: Low-frequency flux saturation and high-frequency leakage loss, ahead of the INPUT control as on the hardware
• Output Stage: Push-pull class A into the output iron - symmetric, so third harmonic
• Noise: Four uncorrelated sources per channel plus a tilted component, -93.7 dBFS
• Thread Safety: Lock-free atomic operations for GUI communication

Project Structure

WetCompressor/
|-- vst3sdk/                    # VST3 SDK (git submodule)
|-- WetCompressor/              # Plugin source
|   |-- source/
|   |   |-- wetcompprocessor.h/cpp     # Audio processing
|   |   |-- wetcompcontroller.h/cpp    # Parameter control
|   |   |-- compengine.h/cpp           # The compressor
|   |   |-- fetcore.h                  # Gain cell, sidechain, transformers, amps
|   |   |-- compknob.h/cpp             # Stepped filmstrip knob
|   |   |-- modeswitch.h/cpp           # FAST / NORMAL / SLOW cluster
|   |   |-- ledmeterview.h/cpp         # LED meters
|   |   |-- wetcompcids.h              # Plugin IDs
|   |   `-- version.h                  # Version info
|   |-- resource/
|   |   `-- wetcompeditor.uidesc       # GUI definition
|   |-- CMakeLists.txt                 # Build configuration
|   `-- build/                         # Build output (generated)
|-- tools/
|   `-- comptest.cpp            # DSP measurement harness, no host required
|-- docs/                       # Panel shot and specification sheet
|-- build.bat                   # Build automation script
|-- install.bat                 # Installation script
|-- LICENSE                     # MIT License
`-- README.md                   # This file

Validation Results

The plugin passes all official VST3 validation tests:

47 tests passed, 0 tests failed

Key validations:

• Valid state transitions
• Proper bus configuration
• Correct parameter handling
• Sample rate support (22.05 kHz - 384 kHz)
• Thread safety
• Preset save/load
• Plugin suspend/resume

tools/comptest.cpp measures the DSP directly, with no plugin and no host: the static transfer curve, gain reduction against time for each timing at sample resolution, distortion against gain reduction split into second and third harmonic, the noise floor and the channel crosstalk.

cl /EHsc /O2 /std:c++17 /I WetCompressor/source tools/comptest.cpp ^
   WetCompressor/source/compengine.cpp

Troubleshooting

macOS Issues

Plugin not appearing in DAW:

• Restart your DAW and rescan
• Check VST3 scan path: ~/Library/Audio/Plug-Ins/VST3/
• Verify the folder contains WetCompressor.vst3

Getting "cannot be verified":

• Only older, unsigned releases do this - see "If macOS still blocks it" above
• Right-click the plugin → "Open" → "Open" to bypass Gatekeeper
• Check DAW console for error messages
• Report issue at GitHub Issues

Plugin crashes DAW:

• macOS 10.13+ (Intel) or macOS 11.0+ (Apple Silicon) required
• Check DAW console for error messages
• Report issue at GitHub Issues

Runtime Issues

No sound output:

• Verify the plugin is receiving audio input
• Check that INPUT is not at the bottom of its travel
• Ensure your DAW is routing through the plugin correctly

Nothing on the gain-reduction meter:

• The threshold is fixed at -20 dBFS. Turn INPUT up until the signal reaches it
• Quiet material may need a lot of INPUT; that is the control working as intended

Distorting more than expected:

• The gain cell bottoms out at 38 dB. Past that, more INPUT buys distortion rather than compression - back INPUT off and make up with OUTPUT

Author

Ronald Klarenbeek

• Website: https://wetvst.com
• Email: contact@wetvst.com
• GitHub: https://github.com/yonie

Trademarks

All product names, trademarks and registered trademarks are property of their respective owners, and any reference to them here describes only the kind of equipment this plugin was inspired by. No manufacturer has endorsed, sponsored or licensed this plugin, and no third-party intellectual property is used in it.

License

MIT License - Copyright © 2026 Ronald Klarenbeek (Yonie)

This project is licensed under the MIT License - see the LICENSE file for details.

Note: This project uses the VST3 SDK which is licensed under a BSD-style license. See the VST3 SDK license files for details on SDK licensing.

Acknowledgments

• Steinberg Media Technologies for the VST3 SDK
• VSTGUI framework for cross-platform GUI support
• The audio plugin development community